The national disease control centre revealed the figures in an outbreak that has already claimed 16 lives over 24 hours.

Last night, German agriculture minister Ilse Aigner said scientists were working non-stop to find the source of the unusual strain of the E coli bacteria -- which is believed to have been spread on tainted vegetables -- and where in the long journey from farm to store the contamination occurred.

German authorities initially pointed to cucumbers from Spain, but further tests showed that those vegetables, while contaminated, did not cause the outbreak.

But officials are still warning Germans to avoid raw cucumbers, tomatoes or lettuce.

Spain says it is not ruling out taking legal action against the German authorities for blaming Spanish vegetables for the outbreak.

Deputy Prime Minister Alfredo Perez Rubalcaba said yesterday: "We do not rule out taking actions against Hamburg authorities who have questioned the quality of our products."

Spain has complained that German authorities pointed the finger at Spanish produce before test result were known.

The allegations have virtually paralysed exports of Spanish fruit and vegetables, causing major financial losses.

E coli is found in large quantities in the digestive systems of humans, cows and other mammals. It has been responsible for a large number of food contamination outbreaks in a wide variety of countries. In most cases, it causes non-lethal stomach ailments.

But enterohaemorrhagic E coli, or EHEC, causes more severe symptoms, ranging from bloody diarrhoea to the rare hemolytic uremic syndrome.

Germany's national health agency, the Robert Koch Institute, said 470 people were now suffering from the syndrome.